Java JMS主题发布/订阅服务器

目前，我已经开始使用ActiveMQ研究JMS主题。我已经通过JAVA代码（如下所述）创建了发布者和持久订阅者，并且在订阅者端也收到了消息

Publisher.Java

public static void createConnectionAndSendMessage(String ipAddress)
    {
        try
        {
            ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory("tcp://"+ipAddress+":61617");

            Connection connection = factory.createConnection();
            connection.start();

            Session topicSession = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
            Topic topic = topicSession.createTopic("Test-Topic");

            MessageProducer producer = topicSession.createProducer(topic);
            producer.setDeliveryMode(DeliveryMode.PERSISTENT);

            ObjectMessage message = topicSession.createObjectMessage();

            TopicTO topicTO = new TopicTO();
            topicTO.setId(i);
            topicTO.setName("Sample");

            message.setStringProperty("s_id", "Sample");
            message.setObject((Serializable) topicTO);                

            producer.send(message);
            System.out.println("message sent successfully");
        }
    }
    catch(JMSException e)
    {
        System.out.println("error :" + e);
    }
}

public void createConnectionAndReceiveMessage(String clientId, String ipAddress)
    {
        try
        {
            ConnectionFactory connectionFactory = new ActiveMQConnectionFactory("tcp://"+ipAddress+":61617");
            Connection connection = connectionFactory.createConnection();
            connection.setClientID(clientId);
            connection.start();            
            Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
            Topic topic = session.createTopic("Test-Topic");

            String selector = "s_id = 'Sample'";
            System.out.println("selector : '"+selector+"'....");
            TopicSubscriber consumer = session.createDurableSubscriber(topic, "Sub1", selector, true);

            consumer.setMessageListener(new TopicMessageListener());            

    }
    catch(Exception e)
    {
        System.out.println("error :" + e);
    }
}

Subscriber.java

public static void createConnectionAndSendMessage(String ipAddress)
    {
        try
        {
            ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory("tcp://"+ipAddress+":61617");

            Connection connection = factory.createConnection();
            connection.start();

            Session topicSession = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
            Topic topic = topicSession.createTopic("Test-Topic");

            MessageProducer producer = topicSession.createProducer(topic);
            producer.setDeliveryMode(DeliveryMode.PERSISTENT);

            ObjectMessage message = topicSession.createObjectMessage();

            TopicTO topicTO = new TopicTO();
            topicTO.setId(i);
            topicTO.setName("Sample");

            message.setStringProperty("s_id", "Sample");
            message.setObject((Serializable) topicTO);                

            producer.send(message);
            System.out.println("message sent successfully");
        }
    }
    catch(JMSException e)
    {
        System.out.println("error :" + e);
    }
}

public void createConnectionAndReceiveMessage(String clientId, String ipAddress)
    {
        try
        {
            ConnectionFactory connectionFactory = new ActiveMQConnectionFactory("tcp://"+ipAddress+":61617");
            Connection connection = connectionFactory.createConnection();
            connection.setClientID(clientId);
            connection.start();            
            Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
            Topic topic = session.createTopic("Test-Topic");

            String selector = "s_id = 'Sample'";
            System.out.println("selector : '"+selector+"'....");
            TopicSubscriber consumer = session.createDurableSubscriber(topic, "Sub1", selector, true);

            consumer.setMessageListener(new TopicMessageListener());            

    }
    catch(Exception e)
    {
        System.out.println("error :" + e);
    }
}

我对以下主题有一些疑问：

我如何检查有多少订阅者使用Java JMS在主题中积极查找消息

如何从主题中获取这些活动持久订阅者列表

我们是否可以选择删除主题中已发布的消息

请在这些上下文中帮助我。

---

提前感谢。

在发布/订阅消息模式中，发布者将不知道任何订阅者。Publisher会将消息发布到代理上托管的主题，代理会将这些消息分发给为该主题注册的任何订阅者。如果某个主题没有订阅者，则该消息将被丢弃

JMS规范没有定义任何可以获取所需详细信息的API。在您的情况下，这样的API将是特定于JMS提供者的活动MQ。此链接可能有用：